钴掺杂MoSe2共生长中氢气的作用分析及磁电特性研究

Effect analysis and magnetoelectric properties of hydrogen in Co-doped MoSe2 Co-growth

采用原位共生长化学气相沉积法,以Co3O4、MoO3、Se粉末为前驱物,710℃下在SiO2衬底上生长掺钴MoSe2纳米薄片,分析讨论氢气含量对其生长及调节机理的影响.表面形貌分析表明,氢气的引入促进了成核所需的氧硒金属化合物以及横向生长中需要的CoMoSe化合物分子的生成;AFM(Atomic Force Microscope)结果表明氢气有利于生长单层二维超薄掺钴MoSe2.随着Co3O4前驱物用量的增加,样品的拉曼和PL(Photoluminescence)谱图分别表现出红移和蓝移现象,带隙实现从1.52—1.57 eV的调制.XPS(X-ray photoelectron spectroscopy)结果分析得到Co的元素组分比为4.4%.通过SQUID-VSM(Superconducting QUantum Interference Device)和器件电学测试分析了样品的磁电特性,结果表明Co掺入后MoSe2由抗磁性变为软磁性;背栅FETs器件的阈值电压比纯MoSe2向正向偏移5 V且关态电流更低;为超薄二维材料磁电特性研究及应用拓展提供了基础探索.

In this paper,Co3O4、MoO3 and Se powders were used as precursors in in-situ co-growth chemical vapor deposition method.Cobalt-doped MoSe2 nanosheets were grown on SiO2 substrate at 710℃.The influence of hydrogen content on its growth and regulation mechanism was discussed.Surface morphology analysis showed that the introduction of hydrogen promoted the formation of oxy-selenium metal compounds required for nucleation and the CoMoSe compound molecules required for lateral growth.AFM(atomic force microscope)results show that hydrogen is beneficial to the growth of single-layer two-dimensional cobalt-doped MoSe2.With the increase of the amount of Co3O4 precursor,the Raman and PL(photoluminescence)spectra of the sample showed red shift and blue shift,respectively,and the bandgap was modulated from 1.52 eV to 1.57 eV.The XPS(X-ray photoelectron spectroscopy)results analysis showed that the elemental composition ratio of Co was 4.4%.The magneto and electric properties of the samples were analyzed by SQUID-VSM(superconducting quantum interference device)and semiconductor parameter analyzer for electrical testing.The results show that MoSe2 changes from diamagnetic to soft magnetic after Co incorporation;the threshold voltage of back gate FETs is shifted by 5 V from pure MoSe2,and the off-state current is lower.This research provides a basis for the research and application development of ultra-thin two-dimensional materials.